Hepatitis B – the oldest human virus

Ana Roibu

Recent studies at the University of Copenhagen, Denmark, have found traces of the Hepatitis B virus (HBV) in 4,500-year-old skeletons. HBV is a double-stranded DNA virus that affects over 300 million people around the world. It is one of the most common causes of liver diseases, such as cirrhosis and liver cancer. The virus, which is carried in blood and bodily fluids, is highly infectious (50-100 x more contagious than HIV). It can survive up to a week outside of the body, including objects and surfaces. Symptoms of infection include fatigue, nausea, jaundice, body aches and fever. With a very complex life cycle, it is one of the few non-retroviral viruses that uses reverse transcription to replicate. Currently, hepatitis B is treated with an injection of immunoglobulin up to 12 hours after infection.  Acute hepatitis B infection usually does not need a treatment, while chronic hepatitis B infection may include antiviral medications such as adefovir and entecavir, or interferon infections, or in very severe cases, a liver transplant.

Up until this week, the hepatitis B virus was thought to be only a few hundred years old. The researchers in Denmark, who published their findings in Nature, sequenced the skeletal remains of 12 individuals ranging from the Bronze Age (2500 B.C) to the Medieval age. This is the oldest evidence of a human virus to be found. HBV is a ‘popular’ virus to research, as the genetic material is composed of DNA rather than RNA, making it possible to detect via standard ancient DNA sequencing methods. As a chronic infectious virus, it stays in the body, especially the bones and teeth, which makes it easy for the ancient DNA researchers to study.

Ancient DNA researchers have raised the possibility of resurrecting the traces of the ancient HBV and test them in mice, to distinguish the similarities and differences between the ancient and modern viruses. This new discovery would allow for a better insight into ancient history, as well as the ability of viruses to survive and be passed on over such a long period of time.

Edited by Karen Yung and Shreya Singireddy